The defining property of dark matter (DM) is that it does not participate in electromagnetic interactions in the same way as visible matter. Nevertheless, experimental and observational constraints are consistent with the possibility that DM particles carry a tiny electromagnetic charge \(\epsilon e\)  with \(\epsilon \ll 1\)  (a so-called millicharge) or a small electric or magnetic dipole moment [1]}, [2]}, [3]}, [4]}. Moreover, if DM consists of several different components, the constraints on any sub-dominant component are substantially relaxed and allow for sizable electromagnetic interactions.
